<?php
class nokhbe_menu_walker extends Walker_Nav_Menu
{
	/*
	 * Add vertical menu class
	 */

	function start_lvl( &$output, $depth = 0, $args = array() ) {
		$indent = str_repeat("\t", $depth);
		$output .= "\n$indent<ul class=\"vertical menu\" data-submenu>\n";
	}
}
function nokhbe_f6_drill_menu_fallback($args)
{
	/*
	 * Instantiate new Page Walker class instead of applying a filter to the
	 * "wp_page_menu" function in the event there are multiple active menus in theme.
	 */

	$walker_page = new Walker_Page();
	$fallback = $walker_page->walk(get_pages(), 0);
	$fallback = str_replace("children", "children vertical menu", $fallback);
	echo '<ul class="vertical menu" data-drilldown="">'.$fallback.'</ul>';
}